DE 32 13 840 Al teaches the application of a foam to the pile side to wash or rinse a textile web of material and then to subject the textile material immediately thereafter to a steam treatment, in order then to rinse it with water to wash out the dissolved contaminants. It is also intended to perform the foam application in two stages, with the first applied foam initially being vacuumed off with the dissolved contaminants or squeezed out of the textile material and only then is the textile material precleaned in this fashion, fed into the steamer with a second applied foam. It is important for both stages that the foam prepared from one or more surfactants that have no affinity for the fibers of the textile material but exhibit a high adsorptivity for the contaminants being washed out, be prepared before the application to the textile material and be merely applied. This method does not ensure any intensive contact between the foam and the fibers of a thick pile, especially not over its complete length down to the roots. Complete cleaning is therefore not possible with this method.
Another treatment method is disclosed in DE 30 26 349 Al which teaches a cleaning method in which a foam is likewise poured onto the textile material, and is worked into the textile material before steaming. This treatment method, which has a pronounced influence on the pile, destroys the pile at least partially and produces a great deal of fluff, so that such working of foam is not suitable for textile materials with a pile.
Of course, the same applies when, as in foam dyeing as known from DE 30 45 644 Al, a liquid is applied to the textile material but the foam must then be produced by fulling or the like on the textile material.